Tempered glass article and method of manufacturing the same



Oct. 24, 1939.

B. LONG TEMPERED GLASS ARTICLE AND METHOD OF MANUFACTURING THE SAME Filed March 29, 1937 fly.

the untempered band thus acting as a Patented Oct. 24, 1939 amass I NT emu 'rsmrsano cuss-sundae arm mrruon' MANUFACTURING THE sans American Secnrit Delaware Application mm]. as.

In France This invention relates to tempered glass and particularly to tempered glass sheets or plates.

' when a tempered glass sheet is broken at any point, the whole sheet'breaks up into small pieces."

{5 This has been found objectionable, for example,

in thecase of glass sheets used as mot'orc'ai'.

1937, April windscreens, for' the reasongthatthe broken sheet usually remains in place and vision through it is.

'. altered.

' 1o Furtherit has hitherto been found impossible t3 cut a tempered glass sheet, since any attempt atcutting leads to fragmentation of the whole edy the above mentioned inconveniences.

The present invention has for its object .tem-

- p'ered glassarticles in whichthe fragmentation is arrested'alongany line by providing the article with-a band of untempered glass along that line, barrier to spread of fragmentation.-

"Accordingto the invention a tempered glass article has areas separated by a band in which I .theglass" is untempered, so -as to prevent frag-' 25 ment'ation which might occur in one rea from spreading to another area separated herefrcm flbyth ebani Inthe'case of windows for motor-cars and particularly of Windshields, it is possible to limit 80. a small surface situated in front of the driver byvided. 7 l 'igureloisavlewofasheet 'tobecutintotwopartax Company, a corporation of sen-1st. uam a. 1m

of glass with sap- Fleur-e4 is a view of a sheet a d m- .And Figure 5 is a view of the same sheet with one area when broken.

Figure 6 is a view of a sheet of glass from which 5 two pieces of predetermined shape are to be divided oh, 1 I j And Figure Tia aviewof the same sheet with the pieces divided on. I

Figure 81s a view of a sheet of glass adapted 10, to be divided into two'parts,

I And Figure] is a view of the same sheet so di- I of glass adapted l 5 Figures 11 and 12 show diagrammatically apparatus for the continuous manufacture of a tempered glass sheet provided with untempered bands to permit it to be cut at desired intervals. In' the shown'in Figures 1, 2 and 3, all

' which surrounds entirely the zone A; this band a has only a width'of some millimeters.- In order 25 to manufacture this windshield according to the invention the band a has been preserved from the thermic treatments which have produced the tempering of theglasssheet in the zones A and B. For example, it is possibleto obtain this re- 39:

sult,.by applying on each face of the glass, plate,

. after the plate has been brought out of the-heat-.

. ing material such as asbestos carried by a movas mit a tempered glass sheet tobe divided along-a predetermined line by'providing on each side of the line, aband' of untempered glass.

' In thefcase' of the continuous manufacture of tempered glass sheet it is possible to form at convenient intervals on this sheet untempered' bands to permit its cutting.

I The untempered bands may be produced either it by preventing'said bands to beitempered during;

ing furnace and before it is submitted to the chilling -operation,-a narrow'band of an'insulatable frame and having thev convenient shape to surround the area A.- Then, theglass sheet is rapidly cooled for example by blowing a cooling fluid by the known apparatus. The asbestos band prevents the rapid cooling of the glass pro- 40. tected by it and the glass is maintained at a high temperature under said band while the parts A- and B are rapidly cooled. The-result is that the bands v and the band ible.

superficial layers of the glass under the band of insulating material are put under tension during 45 their cooling while the superflcialrlayers of the other parts of the glass are put under compression. y I v A windshield made according to the present invention is similar to an ordinary tempered windso shield as-it does not present parts of less visibility surrounding the-acne A is not vis- But if a stone strikes any point of the area 28, so as to break it, fragmentation of. the area 00- 'rollers h. As soon as it has been'formed the curs up to the periphery of the frame a, leaving the area A within the frame intact. The'glass then has the appearance of Figure 2, and clear vision is maintained through the area A. On the other hand, if the area A is struck by a stone so as to break it, fragmentation is limited to the area A and the area B remains intact for clear vision, the glass then presenting the'appflratus of Figure 3. Complete fragmentation of the whole glass can occur only if the stone strikes the band a and since this need not be many millimeters in width there. is only a small chance of this happening.

It is well understood that instead'of dividing the windshield in two parts only, it is possible to divide it into as numerous zones as it may be desired. l

Figures 4 and 5 show a tempered glass sheet which may be used for various applications such as windows, partitions, floors In such appll cations, tempered glass is very advantageous owing to its special properties, s1 ecially its 'me- ,chanical resistance and its elasticity. But, if it occurs a shock whichproduces breaking, the whole partition divided into small pieces and yields.

Figures 4, and 5 represent a sheet of glass in which a plurality of narrow bands 0 are untempered, thus separating the sheet into a plurality of areas C. If the 'glassin any one area C is broken, fragmentation is limited to this area, and the whole" sheet, including the broken area, if held in a frame, will generally remain in place.

The untempered bands. may be given any form and location suited to the particular purpose for which the sheet is intended.

Figures 6 and '7 illustrate one way in which the 'invention may be used to obtain pieces of tempered glass of any desired shape from a sheet of glass. Bands e and 1 being peripheries of the pieces Eland F, respectively, to be obtained are .left untempered. The glass outside these bands is broken, when fragmentation is caused as in Figure 7, leaving the two pieces E and F intact.

Figures 8 and 9 illustrate a method of dividing a single sheet of tempered glass into two. Bands 9 and-g are left untempered, and the narrow stripe of tempered glassbetween the two. bands is broken, as shown in Figure 9, leaving the two pieces G and G intact. Alternatively, abroad band may be left untempered, and the sheet cut into two along ,the line 9 in the centre of the ing means J. In order to reserve nontempered strlpes, narrowfand thin plates K madeof inband, by, for instance, a diamond cut.

Instead of protecting the band of glass during the chilling operation, to prevent its being tempered, it may be protected during the heating operation,to prevent the glass in the band reaching a temperature at which it is tempered by the chilling operation. Alternatively, an untempered band of glass may be. produced in ."l.

tempered sheet by heating the glass in theband locally, as by an electrical heater, In. the case of ordinary glass; it is suilicient to heat the band to about 500 C. for a suitable time, to de-temper it, andthe surface of the glass is not thereby injured. Figure 11 shows execution of this application. An endless glass sheet H is produced by any known drawing meth- 0d from a molten glass bath land it is drawn by glass sheet is subjected to the action of coolsulating substance are applied against the sh et diagrammatically a method of .during the hardening by blasting. These insulating narrow and thin plates, as shown on Figure 11, which may be parts of drawing devices L, correspond, by example, with endless chains which bring them into contact with the glass sheet and move them forward with the speed of the'glass 4 sheet. By this method, untempered glass stripes, single as on Figure 10 or twined as on Figure 8, are obtained from place to place, either uniformly or periodically variably spaced, in order to permit the cutting. I, I

Another method of realization is shown on Figure 12. In this case, the glass sheet H is tempered on its whole area by the cooling means 'J as soon asit emerges from the molten glass bath: Then, the glass sheet goes through an annealing sheath M. Afterwards, the cutting stripes are detempe'red by an application of single or twined heating devices N which are carriedby endless chains which come one after another into contact with the glass sheet and go with it at the same speed Either cutting may be immedi-" 1. A glass sheet for a windshield comprising at least an area in which the glass istempered sur-[ rounded by another area of tempered glass but,

separated from the last mentioned area by a continuous band in which the glass is untempered. 2. A method to divide, a tempered glass article into severalpieces which consists in producing a band in which the glass is untempered along the periphery of each piece t6'be obtained and causing -thefragmentation of the glass in the zones of tempered glass outside these pieces "3. A tempered glass article comprising at least an area in which the glass is tempered surrounded by another area of tempered glass but separated from the lastmentioned area by a band in which the glass is untempered.

4. The method of manufacturing tempered sheets of glass which consists in forming a continuous ribbon of glass and tempering the same by sudden cooling of portions .of the surface thereof while leaving untempered band in such continuous ribbon extending from edge to edge of the continuous ribbon. I

5. The method of producing a shaped article of tempered glass from a larger piece of temperedglass which comprises establishing a zone of untempered glass around the glass which is to form the article and causing fragmentation of the tempered glass exterior to said untempered. area.

I 6, A method to divide atempered glass article into several pieces which consists in producing in said article along the periphery of each piece ftmpered and cutting tempered band.

7'. A method to divide a tempered glass article along the periphery of each piece to be obtained a band in which the glass is untempered and to be obtained a band in which the glass is une gl ass along the un-,'

into several pieces which-consists in producing i 9. The method of manufacturing tempered areas by bandswhich extend from one edge to 10 causing the fragmentation of the glass in the tions of the surface thereof corresponding to zones of tempered glass outside these pieces. the size of the sheets to be obtained while leav- 8. A method to divide a tempered glass article in; untempered bands in such continuous ribbon into at least two 'pieces along a determined line extending from edge to edge of the ribbon, and

I 5 which consists in producing on each side of said cutting the ribbon in said bands. 5 line bands in which the glass is untempered, said; 10. A glass sheet comprising areas in which bands being separated by a strip of tempered the glass istempered, at least "one of these areas glass, and in causing the breakage of the glass extending from one edge of the sheet to another in the said tempered strip. and being separate from the adjacent tempered sheets of glass which consists in forming a conanother and in which the glass is untempered. tinuous ribbon of glass and suddenly cooling por- BERNARD LONG. 

